Taxonomy And Phylogeny Of Major Taxons Of Benthic Ciliates On The Coast Of The Yellow Sea

Marine microbenthos, represented by ciliated protozoa, are important components in the process of material recycle and energy flow in benthic microbial food webs. Because of the complexity and diversity of marine benthic environment, multiple kinds of habitats exist for various ciliates. Previous research has shown that benthic ciliates have higher diversity and abundance than planktonic ones. Nevertheless, due to the undersampling and misidentification, only a small part of benthic ciliates were reported.This work includes morphological and molecular data of ciliates sampled from from different habitats, such as beaches, reefs, estuaries and docks in Qingdao, Yancheng, Dongying, Weihai and other regions in the Yellow Sea during July 2012 to October 2015. Live observation and protargol impregnation were used to reveal the living features and ciliary pattern. Improves diagnosis are provided for misidentified species and ones with confusing morphological feature. SSU rRNA,ITS1-5.8S-ITS2,LSU-rRNA gene were sequenced for sequence alignment, secondary structure prediction and construction of phylogenetic trees for phylogenetic analyses. Main results include morphology and molecular phylogeny:In the morphological part, 30 species of 20 genera, belonging to Hypotrichia, Heterotricha and Cyrtophoria are described in detail, which include:1. Establishment of 3 new speciesCaudiholosticha marina n. sp., Caudiholosticha monilata n. sp. and Nothoholosticha flava n. sp. are established based on morphological and SSU rDNA information.2. Redescription of 3 species and reestablishment of one speciesRe-establishment of Pseudokeronopsis pararubra Hu et al., 2004 is conducted based on the population isolated from Qingdao. Invastigate and improved diagnosis of P. carnea(Cohn, 1866) Wirnsberger et al., 1987, P. rubra(Ehrenberg, 1836) Borror & Wicklow, 1983 and Parabirojimia similis Hu et al., 2002 are provided, together with systematic review of Pseudokeronopsis.3. Records of 3 speciesAnteholosticha multicirrata Park et al., 2013, Oxytricha longa Gelei & Szabados, 1950 and Sterkiella thompsoni Foissner, 1996 were first found in China with morphological information based on living observation and infraciliature.In the molecular phylogenetic part, 45 species of 19 genera were sequenced and 45 SSU rDNA, 22 ITS1-5.8S-ITS2 region and 22 LSU-rDNA sequences were added. Sequence alignment, secondary structure prediction and construction of phylogenetic trees were conducted for phylogenetic analyses. The results are following:1. In the Hypotrichia, ITS1-5.8S-ITS2 region sequences poccess obvious divergent distance gap to discriminate close species in Pseudokeronopsis with the second structure of ITS2 as assistant. Pseudokeronopsis sequences in Gen Bank were revised with transferring and removing of sequences of misidentified species. Phylogentic analyses based on SSU rDNA sequences supports the polygeny of Caudiholosticha and the systematic status of Nothoholosticha with hypothesis that presence or absence of frontoterminal cirri is not a key feature to distinguish genera of the subfamily Nothoholostichinae.2. Phylogenetic analyses with adding SSU rRNA gene sequences of four Condylostoma species rejected monophyly of Condylostoma, but its monophyly need more molecular information especially that of the type species.3. Monophyly of Dysteriidae, Hartmannulidae, Chlamydodontidae and Chilodonellidae in Cyrtophoria was supported and monophyly of Chlamydodontida was rejected by phylogenetic analyses with adding SSU rDNA sequences of six species.